This invention relates generally to pulse type high voltage transformers and specifically to such high voltage transformers for use in television receivers. A color television receiver typically has a high voltage system that develops from 25-33 kilovolts DC for operation of the cathode ray tube. A conventional high voltage transformer includes three or more secondary windings, serially connected with suitable high voltage diodes, that are magnetically linked to a primary winding. The transformer is either a bobbin wound type or a layer wound type. The layer wound transformer is optimum in terms of leakage inductance and distributed capacitance, but suffers the disadvantage of requiring a large number of layers of very fine wire that are separated by layers of insulation from each other and from the primary winding. Such transformers are difficult to manufacture, require a larger number of diodes and connections and are quite expensive. The bobbin wound transformer includes one or more secondary windings that are prewound on bobbins and subsequently mounted on a magnetic core to link with the primary winding. The nature of a bobbin wound secondary is such that many of the coil turns are relatively far from the primary winding, resulting in an undesirably high leakage inductance. The bobbin winding however is much easier to manufacture.
With the present invention, a hybrid transformer is provided which achieves the benefits of both types of transformers. Very specifically, it combines the low leakage and uniformity of a layer wound transformer with the low cost and manufacturability of a bobbin wound transformer.